Objectives are to define which subcellular constituents of animal and human granulocytes possess biologically active substances affecting blood coagulation, determine if macrophages have these same biological activities and to examine the influence of endotoxin and certain drugs on procoagulant activity of leukocytes. Blood leukocytes will be isolated by Dextran sedimentation and differential centrifugation on Ficoll-Hypaque gradients. Lysosomes will be obtained from disrupted cells by differential centrifugation and separated into distinct populations on continuous sucrose density gradients; these will be monitored by light and electromicroscopy. Soluble extracts of lysosomes will be separated by column chromatography into fractions for biological testing.